1. Field of the Invention
The present invention relates to a method and a circuit for physical uplink transmission for 3GPP long term evolution (LTE), and more specifically, to a method and a circuit generally adept at remapping physical uplink control channels for both of a resource block containing acknowledgement and non-acknowledgement (ACK/NAK) channels and a mixed resource block containing the ACK/NAK channels and channel quality indication (CQI) channels.
2. Description of the Related Art
Orthogonal Frequency Division Multiplexing (OFDM) is a popular wireless communication technology for multiplexing data in the frequency domain.
The total bandwidth in an Orthogonal frequency-division multiplexing (OFDM) system is divided into narrowband frequency units called subcarriers. The number of subcarriers is equal to the FFT/IFFT size N used in the system. Generally, the number of subcarriers used for data transmission is less than N because some of the subcarriers at the edge of the frequency spectrum are reserved as guard subcarriers, and generally no information is transmitted on these guard subcarriers.
The Third Generation Partnership Project Long Term evolution (3GPP LTE) is a project within the Third Generation Partnership Project to improve the Universal Mobile Telecommunications System mobile phone standard to cope with future requirements. In the standards of the physical uplink of 3GPP LTE (long term evolution), one type of the resources used for transmitting the uplink control channel (PUCCH) is known as a cyclic shift (CS) for each OFDM symbol. One of important aspects of the system design is resource remapping on either a symbol, slot or subframe-level.
The following three references are cited as being exemplary of contemporary practice in the art:
Reference [1], R1-081155, “CR to 3GPP spec 36.211 Version 8.1.0”, RAN1#52, February 2008, Sorrento, Italy, describes the standards of the physical channels for 3GPP, and chapter 5.4.1 will be cited in the following specification in order to illustrate the contemporary slot-level remapping method for the acknowledgement and non-acknowledgement (ACK/NAK) channel in the physical uplink of 3GPP LTE system.
Reference [2], R1-080983, “Way-forward on Cyclic Shift Hopping Pattern for PUCC”, Panasonic, Samsung, ETRI, RAN1#52, February 2008, Sorrento, Italy, discloses methods for remapping either a resource block containing only ACK/NAK channel or a resource block containing both CQI and ACK/NAK channels.
Reference [3], R1-073564, “Selection of Orthogonal Cover and Cyclic Shift for High Speed UL ACK Channels”, Samsung, RAN1#50, August 2007, Athens, Greece, teaches a scenario for data transmission for high speed uplink ACL/NAK channel by using a subset of the combination of the cyclic shift and the orthogonal cover.
The methods of the slot-level resource remapping recently proposed, for example as disclosed in references [2] and [3], have been included in the 3GPP standards as shown in reference [1]. One of the shortages of transmission capacity in wireless telecommunication networks is that the contemporary remapping methods for resource blocks containing control channels are designed exclusively for either ACK/NAK resource blocks with the extended cyclic prefix or for normal cyclic prefix cases where a mixed resource block containing both of the ACK/NAK and CQI channels, but contemporary remapping methods are not applicable for both. This shortage in transmission capacity prevents the contemporary techniques from being readily adapted to a complex 3GPP LTE physical uplink where ACK/NAK resource blocks may be applied by the extended cyclic prefix, adapted to a complex 3GPP LTE physical uplink where mixed resource blocks (where the ACK/NAK and CQI channels coexist) may be applied by the normal cyclic prefix, and adapted to a complex 3GPP LTE physical uplink where mixed resource blocks (where the ACK/NAK and CQI channels coexist) may be applied by the extended cyclic prefix.